This invention relates to drum support apparatus and more particularly to supports for photosensitive drums to prevent drum run-out.
In present reproduction machines, a problem has been encountered with photoreceptor drum radius run-out. The reason for the problem lies with the drums and how they are handled in manufacturing and in the field. Hitting the rim of the drum deforms the counterbore, and an out-of-tolerance condition occurs when conventional endbells, interference fitted with the drum, are reassembled in the drum. This is especially true of the inboard endbell in a number of reproduction machines, which is concave by about 5 inches. A slight cock in its assembly throws its shaft support bearing off center considerably due to magnification of the error by the length of the concavity. Since in a number of reproduction machines a shaft that is journaled to the machine frame is cantilevered from the frame to support the photoconductivity drum without exterior support, more runout is observed on the inboard side of the photoconductor drum than on the outboard side.
A solution to the above-mentioned problems of drum run-out is particularly desirable for reproduction machines incorporating magnetic brush rollers in the development process instead of cascade development because reducing the radial drum run-out minimizes the effects of the drum tolerances on the spacing between the drum and the magnetic rollers.
Accordingly, it is an object of the present invention to provide a drum support apparatus that reduces drum run-out.
Another object of this invention is to reduce copier maintenance in the field.
Yet another object of this invention is to maintain the outside surface of the drum concentric relative to the shaft from which the drum is supported and thereby decrease the possibility of incurring drum run-out.
A still further object of this invention is to minimize the radial run-out of a copier drum by installing at the manufacturing site and shipping to the field, drums with pre-assembled interior webs.